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- Table of Contents
MED13 / Mediator of RNA polymerase II transcription subunit 13 · Western blot design guide
Design a Western Blot for MED13
Source-linked MED13 Western blot protocol options, expected-band and isoform facts, troubleshooting for weak or shifted signal, and recommended anti-MED13 WB antibodies. Everything you need to plan the experiment before you commit precious samples.
Evidence assembled September 2026 · For research use; verify linked source records and product datasheet before use
MED13 Western Blot Experimental Design Guide
Expected bands, source-linked protocol options, controls and antibodies — the at-a-glance facts below, then the full design guide.
Must know before running
| Expected band | ~239.3 kDa | |
| Observed band | ~300 kDa | |
| Gel | 5–20% (catalog A04545-1) | |
| Negative control | Suggested KO / knockdown lysate |
Important caveats
Reasons your observed band may differ from the expected size.
| PTM | Phosphorylated | |
| Caveat | Phosphorylation-state controls | |
| Gene-set association | MSigDB C7 membership | |
| Isoform | 1 isoform(s) |
Section 1
Source-Linked MED13 Western Blot Protocol Options
The A04545-1 protocol combines labelled catalog values with standard starting conditions. Published comparisons retain their own sample, reagent and detection scope.
| Sample / lysate | human U2OS, human MCF-7 (catalog A04545-1) |
| Gel % | 5–20% (catalog A04545-1) |
| Load | 50ug; reducing conditions (catalog A04545-1) |
| Transfer | a Nitrocellulose membrane at 150mA for 50-90 minutes (catalog A04545-1) |
| Membrane | Nitrocellulose membrane (catalog A04545-1) |
| Blocking | 5% Non-fat Milk/ TBS for 1.5 hour at RT (catalog A04545-1) |
| Primary antibody | A04545-1 · 0.5 ug/mL (catalog A04545-1) |
| Primary incubation | overnight (catalog A04545-1) |
| Secondary antibody | goat anti-rabbit IgG-HRP, 1:10000 (catalog A04545-1) |
| Secondary incubation | 1.5 hour at RT (catalog A04545-1) |
| Wash | TBS-0.1%Tween 3 times with 5 minutes each (catalog A04545-1) |
| Detection | ECL (catalog A04545-1) |
Section 2
What Is the Expected MED13 Western Blot Band Size?
MED13 is predicted at 239.3 kDa and observed near 300 kDa on Western blots; the cause of the difference is not established.
| Band near 300 kDa | Empirical MED13 band reported in whole-cell lysates; confirm identity with antibody controls |
| Band near 239 kDa | Near the predicted mass of full-length MED13; identity still requires confirmation |
| Little or no band in a cytoplasmic fraction | Consistent with MED13's nuclear location |
| Additional closely spaced band | Could reflect a different phosphorylation state, but distinct migration is not established |
💡Expected MED13 appearanceMED13 has a predicted mass of 239.3 kDa, while antibody QC reports a band near 300 kDa in whole-cell lysates; the cause of the difference is unestablished, so confirm identity with ordinary antibody controls.
| Predicted full-length mass | 239.3 kDa is the sequence-based reference, while the empirical band is near 300 kDa |
| Phosphoserine at residue 395 | May affect migration, but no visible shift is established |
| Phosphoserine at residue 500 | May affect migration, but no visible shift is established |
| Phosphoserine at residue 504 | May affect migration, but no visible shift is established |
| Situation | Likely cause | Next action |
|---|---|---|
| No band in lysate | Nuclear MED13 may be poorly recovered | Check nuclear protein recovery and include a positive-control lysate |
| Band higher than expected | The reported band is near 300 kDa, above the 239.3 kDa prediction; the cause is unestablished | Compare with the reported band and confirm identity using an independent antibody or MED13 depletion |
| Band lower than expected | Possible protein fragmentation; no cleaved MED13 product is specified | Check sample integrity and confirm identity with an independent antibody |
| Multiple bands | Phosphorylation sites are present, but distinct migrating forms are unestablished | Compare with MED13-depleted lysate to identify the specific band |
| Weak or no signal | Insufficient nuclear protein recovery or detection sensitivity | Verify nuclear protein recovery and use a positive-control lysate |
Experiment evidence
Western blot images showing MED13 band
A04545-1 · MED13
← swipe / scroll for more images →
Real WB data behind the band-size expectations in this section.
Sample controls for MED13 Western blot
🧪For positive controls for MED13 in Western blot, you can use no HPA-supported sample because tissue and cell expression data are unavailable.
Positive control: No high/medium HPA tissue identified
Negative control: Suggested KO / knockdown lysate
Loading controls: Run GAPDH, β-actin, and a total-protein stain alongside.
⚠️Feasibility: HPA expression data are unavailable, so tissue control selection is uncertain.
HPA tissue expression evidence for MED13
Comprehensive Human Protein Atlas IHC scoring per tissue. Rows are taken directly from the HPA tissue chart — click any row's HPA link to view the source.
Higher expression tissues · candidate positive controls from IHC
| Tissue | Cell type | Level | Evidence | Source |
|---|---|---|---|---|
| No high/medium HPA tissues identified in the supplied evidence. | ||||
Lower expression tissues · IHC evidence, not confirmed WB-negative controls
| Tissue | Cell type | Level | Evidence | Source |
|---|---|---|---|---|
| No lower-expression tissue rows available in the supplied evidence. | ||||
Section 3
Advanced MED13 Western Blot Tips
Deeper troubleshooting and optimisation questions for MED13, answered from its protein features.
How should MED13 band migration be interpreted?
Band shift · Use the separately labelled calculated mass and catalog-observed evidence above. A sequence annotation does not establish an observed migration shift. Verify target identity with orthogonal controls.
Could another MED13 isoform explain an additional band?
Isoforms · The supplied features list one isoform and no alternative sequence. They therefore provide no basis for assigning an additional band to another MED13 isoform.
Which MED13 phosphorylation sites matter when interpreting bands?
PTM · UniProt lists phosphoserines at positions 395, 500, 504, 530, 537, 826, 890, and 1029. These are UniProt coordinates; antibody or paper numbering may differ. Their annotation alone does not establish a visible mobility shift.
Does this guide establish induction of MED13?
Induction · No general induction response is established by this guide. A pathway or gene-set association is not evidence of induction in a particular specimen. Verify the relevant treatment and control in a target-specific experiment.
What transfer method to use for MED13 Western blot?
Transfer · MED13 is a large protein with a predicted mass of 239.3 kDa and an observed band near 300 kDa. Choose and check transfer conditions for that size range, using a high molecular weight marker and checking how much protein remains in the gel.
How should blocking be optimized?
Blocking · Standard workflow guidance: follow the A04545-1 datasheet where specified. Otherwise compare 5% milk or 5% BSA in TBST; for a phospho-specific assay start with BSA. Optimize background and specific signal with matched controls.
How should MED13 bands be quantified?
Quantitation · Quantify the consistently identified MED13 band near the supplied observed position of 300 kDa. Keep the band selection consistent across samples; the predicted 239.3 kDa mass alone does not identify a separate band as MED13.
Why might MED13 appear near 300 kDa instead of 239.3 kDa?
Interpretation · The supplied observed band is approximately 300 kDa, while the predicted mass is 239.3 kDa. MED13 has annotated phosphorylation sites, but these features alone do not establish the cause of the difference. Use the observed position as a reference and assess band identity independently.
Compare them with the approximately 300 kDa observed band and the 239.3 kDa predicted mass. The supplied features list one isoform and eight phosphoserines, but do not establish the identity or cause of another band. Avoid assigning it to an isoform or phosphorylation solely from its position.
Compare them with the approximately 300 kDa observed band and the 239.3 kDa predicted mass. The supplied features list one isoform and eight phosphoserines, but do not establish the identity or cause of another band. Avoid assigning it to an isoform or phosphorylation solely from its position.
Boster reagents
MED13 Western Blot Antibodies
Catalog antibodies with Western blot application and product-specific WB images. Evaluate suitability with the reported sample, controls and experimental conditions.
Real WB data
Anti-MED13 Antibody Picoband®
Cat # A04545-1
A04545-1 is a rabbit polyclonal anti-MED13 antibody listed for human and mouse. Its Western blot image uses human U2OS and MCF-7 whole-cell lysates and shows a band near 300 kDa, above the expected 239 kDa; mouse WB evidence is not shown.
Which to pick: A04545-1 is the only listed MED13 antibody and has a WB image from human U2OS and MCF-7 lysates. For mouse samples, reactivity is listed, but the supplied image does not demonstrate mouse performance.
Source: BosterBio MED13 gene-info card — filtered to Western-blot-capable antibodies; each card shows that product's actual WB validation figure.
References
- UniProt Consortium. UniProt entry Q9UHV7.
- Human Protein Atlas. MED13 tissue expression.
- PMC13000170 — target-verified WB comparison
- PMC5973976 — target-verified WB comparison
- PMC7897519 — target-verified WB comparison